104 THE INDIAN JOURNAL OF VETERINARY SCIENCE AND ANIMAL HUSBANDRY [ III, I

of the parasite is due to the lack of the proper anatomical details being available
even up to the present day. Cobbold's original description was too brief and his
figure shows only the alimentary system completely. Evans and Rennie [1909]
have published slightly better figures and have given a little more detailed account
of the parasite, but these authors too are silent upon certain anatomical details of
the parasite which are of importance from the taxonomic standpoint in this group
of animals. The present opportunity is therefore taken to fill up the missing gaps
in the description of the parasite, which might facilitate the task of a systematist.

The worms are pinkish in colour, but appear to be of olive green colour when
filled with bile. When flattened some worms appear to be perfectly round, while
others present a somewhat pear-shaped appearance. In the majority of specimens
there is a tendency for the anterior and posterior ends to curl down ventrally.
In some cases the cephalic end is distinctly set off from the rest of the body and
in such cases the shoulders are very well defined. In others which have a pear-
shaped body the cephalic end cannot be so well distinguished from the rest of the
body and consequently the shoulders appear to be either indistinct or absent.
This indistinct nature of the shoulders or their complete absence in some cases
together with the shape of the ventral sucker and the ignorance regarding the pre-
sence or absence of the receptaculum seminis may have led some observers to
regard it as a member of the genus Fasciolopsis.

The worms measure 12—14* in length and 9—12.5 in breadth. Their thick-
ness in the preserved material is about 1.5—2 in the centre of the body. The whole
body is covered with a thick cuticle beset with close-set alternately transverse
rows of spines. These measure 0.042—0.055 in length and 0.009—0.017 in thick-
ness. They do not present a specially stouter appearance on the dorsal side than
those on the ventral one, as remarked by some authors, nor is this variation in
size noticeable between those at the anterior end and those at the posterior one.

The mouth is situated at the anterior end and is 0.3 wide. It is surrounded
by an oral sucker which is elliptical in shape and measures 0.52—0.64 × 0.33—0.43.
The pharynx is large, situated behind the oral sucker and measures 0.38 — 0.52 ×
0.22 — 0.38. The œsophagus is very short. The intestine is branched both in-
ternally and externally, but the branches on the outer side are more profuse than
those on the inner one.

The ventral sucker is 1.18 — 1.41 × 0.97 —1.07. Its cavity is somewhat
triangular and in some cases a notch is seen posteriorly. The genital pore is si-
tuated at about 2.5 from the anterior end.

                        * All measurements in millimeters.